AlxGa1−xN bulk crystal growth: Crystallographic properties and p–T phase diagram

The recent results on the growth of the AlxGa1−xN bulk single crystals (0.22≤x≤0.91) from solution in liquid Ga under high nitrogen pressure are discussed. We focus on the influence of temperature and the choice of the Al source on the crystal growth. The experiments involving different sources of aluminum such as Al metal, pre-reacted polycrystalline AlyGa1−yN and AlN powder are compared. The best results were achieved using pre-reacted polycrystalline AlyGa1−yN or/and AlN. Single-crystal structure refinement data of these AlxGa1−xN crystals are presented. We also update the p–T phase diagram of (Al,Ga)N compound at high N2 pressure for various Al content, which is the basis for (Al,Ga)N synthesis.